1. Filed of the Invention
The present invention relates to a conveyer belt for conveying sheet material such as cut paper sheet mounted thereon, and relates also to a sheet-material conveying mechanism including a belt conveying device using the conveyer belt and a transfer device for discharging the sheet material such as photosensitive material on to a conveying face of the belt in a direction transverse to the belt.
2. Description of the Related Art
A conveyer belt employed in a conveying line of a photographic processing system for conveying photosensitive material includes a flat conveying face having a uniform coefficient of friction over the entire surface thereof. In general, the print paper is conveyed while being pinched between the conveyer belt and press rollers disposed in opposition to the belt by a disposing pitch which is shorter than the length of the conveyed object, i.e. the print paper. Thus, in order to allow the print paper to be conveyed without slipping displacement, it is necessary that the entire conveying face of the belt have a uniform coefficient of friction. If a larger coefficient of friction is obtained by means of e.g. an adhesive layer so as to retain the print paper more reliably on the conveying face, this will cause a problem in a discharging operation of the print paper off the conveying face. For this reason, conventionally, there has been taken no specific measure for increasing the friction coefficient of the conveying face of the belt.
A photosensitive-material conveying mechanism to be incorporated at a final stage of the conveying line of the photographic processing system functions to feed a finished print paper to a sorter conveyer, and includes a belt conveyer device connected with the sorter conveyer and a transfer device for discharging the photosensitive material on to the conveying face of the conveyer belt in a direction transverse to the belt. The transfer device is connected with the conveying line and functions to discharge or drop print papers as conveyed on the conveying line one after another on to the conveying face of the belt conveying device. Then, each dropped print paper is conveyed on the belt in a direction perpendicular to the conveying or discharging direction of the transfer device.
Accordingly, in this belt conveying device, the press rollers cannot be disposed in the area where the print papers are dropped from the transfer device, hence, at least within this particular area, the print paper is conveyed as being just placed on the conveyer belt without being pinched between the belt and the press rollers.
With improvement of performance of the photographic processing system, the conveying speed of the belt conveyer device too has been increasing. Further, when the print paper is dropped on the conveying face, the print paper is warped upwardly. Thus, the paper contacts the conveying face for a very limited area. In addition, as the paper is conveyed on the conveying face, the paper is subjected to an upward lift due to air coming under it. For these reasons, the paper tends to slip or be displaced or more typically, pivoted on the conveying face. Especially, if the print paper is pivoted in such a manner that its leading end is oriented toward the transfer device, the leading end of the print paper may accidentally come into contact with an obstacle such as a roller of the transfer device, then, the print paper will be displaced or even turned over in the worst possible case.